Electron tubes



J. w. SKEHAN June 9, 1959- ELECTRON TUBES Filed Feb. 2, 1956 2 Sheets-Sheet l K MAG 1 INVENTOR.

JOSEPH W. SKEHAN ATTORNEYS J. W. SKEHAN ELECTRON TUBES June 9, 1959 2 Sheets-Sheet 2 Filed Feb. 2, 1956 FIG.

INVENTOR.

JOSEPH W. SKEHAN ATTORNEYS United taes 2,890,366 Patented June 9, 1959 lice ELECTRON TUBES Joseph W. Skehan, Stamford, Conn., assignor toMachlett.Laboratories, Incorporated, Springdale, Conn, a corporation of Connecticut ApplicationFebru'ary 2, 1956,-Serial No. 562,961

7 Claims; (Cl. 313-146) This inventionrelatesto improvements in supporting means for'an electrode in an electron tube envelope and has particular referenceto novel means for controlling theposition of a grid electrode with respect to other electrodesywithin the envelope of an-electron tube.

In the presently described structure one of the electrodes, preferably the grid, is. mounted on an adjustable support so that it may be tilted whereby diiiiculties arising from; deviations from parallelism between elongated coaxial electrodes mounted within one another are overcome and shorting of the electrodes is avoided. Extreme precision in the manufacture and pre-assembly of such structures is not required,- and the resultant cost of the tube is decreasedwhile the life thereof is substantially increased.

Self-supporting filament-structures for use in electron tubes. sometimesinclude a plurality offilaments of tungsten-wire-which-extend in substantially parallel relation throughout the major portions of their lengths from supports-to which theyaresecured at one end. The end portions'of thefilaments remote from-the supports converge and are connected together at the axis of the series, thus formingv a cagelike filament structure. Such a filament structure, in an electron tube of the presently described type-extends along the axis of the tube within a hollow anodevinpredetermined spaced relation thereto.

The gridelectrode, in triodes of the presently described type-,isalso a'cagelike-structure which is mounted over the filamentstructure, between it and the anode. Grid electrodes are necessarily relatively closely spaced to the filaments audit is, therefore, necessary to so mount the gridthat the spacingbetween-it and the filament structure issubstantially uniform :throughout their adjacent lengths. Furthermore, itis essentialthat a supporting structure forthe grid be-used whichis relatively rigid and yet will maintain the desired space relationship between the electrodesduringthe life of the tube.

The present inventionis-concerned with a grid support which comprises atubular support member having an outwardly extendingannular flange which is turned back on itself to form. an annular seat portion. Theseat portion is rigidly mounted-.on a fixed grid-supporting ring and the grid structure is fixed to the tubular support member. The outwardly extending flange is adapted to be moved at selectedpoints throughout the annulus toward or away from the seatportion. This movement is accomplished by means such. as adjusting screws or the like at the selected points and the inherent resiliency of the device causes the'tubular support member and grid structure to betilted as desired, thus permitting the grid structure to bepositioned in desired spaced relation to the filament structure.

Various-means and methods of assembling grid and cathode electrodes in predetermined spaced relation are to befonnd'in the-prior art. However, none of the known prior 'metli'ods'has been entirely satisfactory. Some have 1 required a multiplicity of parts, others required the manufacture of parts which were necessarily difficult and expensive to form, and still. others were, of such a complicated nature as to requireextraordinary skill in assembling the electrodes.

Therefore, itis accordingly an objectof this invention to provide'a novel adjustable support for an electrode which is relatively simple in .its construction, efiicient in its use, easily operated, and. relatively economical to manufacture.

Other objects. and advantagesof this invention will become apparent from the followingdescription takenin connection with the accompanying drawings wherein Fig. 1,. is an axialsectional view of an electron tube embodying a preferred form of the invention;

Fig. 2 is ahorizontal sectional view taken substantially on line 2-,-2 of Fig. land looking in the direction of the arrows;

Fig. 3 is a horizontal sectionalview taken substantially on line.33 of Fig. 1 looking in the direction of the arrows;

Fig. 4 is an enlargedfragmentary sectional view taken substantially on line, 4-4 of Fig. 2 and looking in the direction of the arrows;

Fig. 5 is a. view similar, to Fig. 4 illustrating the adjustability of the device; and

Fig. 6 is an enlarged fragmentary sectional view taken substantially on line 66 of Fig. 2 and looking in the direction of the arrows.

Referring more particularly to, the drawings wherein like characters of reference designate like parts throughout the several views, the tube shown in Fig. 1 comprises an envelope made up of ametallic anode 10havingone end connected by an annular glass-to-metal seal 11, to one end of a glass bulb 12. The opposite end of the bulb 12 is sealed by an integral wall 13 through which extend a plurality. of, posts, the presently described tube employing six suchvposts. Four of the, posts, designated by numeral 14, function as grid terminals while the re maining posts 15 and 15;; are filament terminals. The posts are vacuum-sealed in wall 13' by-suitable metal-toglass seals 16.

The inner end of filamentterminal post 15 is mounted withina lug 17 on a radially extendingportion of a. filament-supporting plate 18 (Figs. 1 and 3), and post 15a is similarly mounted within a lugv 19 on a radially extending portion of a second filament-supporting plate 20. Plate 18 overlies plate 2.0'substantially on the longitudinal axis of the tube and the radially. extending portions thereof are spaced to permit proper location of the terminal posts 15 and 15a.

The cathode structure embodies a plurality of filament wires, preferably twelve in number, which extend longitudinally of the tube substantially parallel with the axis thereof. The ends of alternate wires 21 are attached by suitable clips 22 to the ends of respective filament-supporting rods 23 which are mounted at their opposed ends in plate 18, the rods 23, being spaced equidistant in a circular configuration. The other filament wires 24 extend parallel With and alternately betweenrwires 22 and are similarly attached by clips 25 to rods 26- which extend freely through openings or notches 27 in plate 13 and are mounted in plate 20. Attheirends remote from the plates 13 and 2d the wires ZZand 24 are bent inwardly to converge and are secured together at acommon central point 28.

The filament structure lies within a grid structure comprising a plurality of wirelike supports, preferably four in number, which are'fixedly secured at one end to the inner side of a tubular metal support or shield 3,0 as by being soldered within inwardly struck portions 31 of the shield. The other ends of the wirelike supports 29 are held in position by a cap 32 to which they are secured,

and a relatively thin grid wire 33 is wound helically around the supports 29, forming a cagelike grid.

In a self-supporting grid structure of the kind described, it is essential that the grid wires and filament wires be maintained apart at a uniform distance through out the adjacent lengths of the wires. Therefore, to provide means for aligning the grid and filament structures, the grid-supporting shield 30 of the present invention is formed with an outwardly extending substantially planar flange 34 which is turned inwardly on itself to form a concentric annular substantially planar seat 35 which is normally spaced slightly from the flange 34 and is resiliently connected thereto by the integral annular portion 36 (Figs. 1, 4 and The shield 30 is mounted on a supporting ring 37 by means of screws 38 (Figs. 2 and 6) which extend freely through openings in the flange 34 and secure the seat 35 directly onto the ring 37. Short radially extending lugs 39 (Fig. 1) are screwed to the underside of the ring 37 and have openings within which are rigidly mounted the inner ends of the grid terminal posts 14 whereby the entire grid structure is supported by the posts 14.

The filament supporting plates 18 and 20 are connected together on the axis of the tube by a metal bushing 41 which is insulated from plate 18 by insulating rings 42. Mounted in the bushing 41 is a stem 43 which extends into the filament structure and carries a planar heat shield 44 at its inner, end.

In mounting a grid'structure in place over a filament structure, it is often necessary to provide means for angling the grid with respect to the filament in order to properly space the electrodes. For this purpose, a plurality of adjusting screws 40 are mounted at spaced intervals in the ring 37 (Figs. 4 and 5), the shanks of the screws extending freely through openings in the flange 34 and seat 35 and threadedly engaging the ring 37 (Figs. 4 and 5). The heads of the adjusting screws engage the outer surface of the flange 34 and by threading the screws into the ring 37 the flange can be made to move toward the seat 35 through the inherent resiliency of the device. In this manner one or more of the screws 40 can be adjusted to cause tilting of the shield 30 and of the grid structure as indicated exaggeratively in Fig. 5, wherein it can be seen that such tilting of the grid structure is about a point which lies substantially on the axis of the structure in a plane normal to the axis and passing through the grid-supporting shield 30. With a device of this type, an electrode can the easily adjusted with respect to another electrode, with resultant increase in efficiency of the functioning of the tube.

It will be apparent from the foregoing description that the objects of this invention have been accomplished by the novel and useful means set forth.

While the novel features of the invention have been shown and described and are pointed out in the annexed claims, it is to be understood that various omissions, substitutions and changes in the construction and arrangement of the parts shown and described may be made by those skilled in the art without departing from the spirit of the invention. Therefore, it is to be understood that all matter shown or described is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A device for supporting an electrode within the envelope of an electron tube, the device comprising a support located in spaced relation to one end of the electrode, and a flexible annular member having the electrode fixed thereto mounted on the support, portions of the annular member being individually adjustable toward and away from the support, the electrode being tiltable upon atjustment of said portions about a point located substantially on the axis of the electrode and in a plane normal to the axis and passing through the device.

2. A device for supporting an electrode within the envelope of an electron tube, the device comprising a sup- .4 port located in spaced relation to one end of the electrode, a flexible annular member having the electrode fixed thereto mounted on the support, portions of the annular member being individually adjustable toward and away from the support, the electrode being tiltable upon adjustment of said portions about a point located substantially on the axis of the electrode and in a plane normal to the axis and passing through the device, and means connected with the annular member for retaining said portions and the electrode in adjusted positions.

3. A device for supporting an electrode within the envelope of an electron tube comprising an annular mount, an annular support member on the mount and embodying a substantially planar annular seat secured to the mount and a substantially planar ring in spaced overlying relation to the seat and resiliently connected thereto, the ring having portions individually adjustable toward and away from the seat, the electrode being mounted upon the ring and tiltable upon adjustment of said portions about a point located substantially on the axis of the electrode and in a plane normal to the axis and passing through the device, and adjustment means connected to the ring for adjusting the portions of the ring with respect to the seat and for retaining the portions and electrode in adjusted positions.

4. A device for supporting an electrode within the envelope of an electron tube comprising an annular plate, an annular support member on the plate and substantially concentric therewith and embodying a substantially planar annular seat secured directly to the plate and a substantially planar concentric ring in spaced overlying relation to the seat and resiliently connected thereto, the electrode being mounted upon the ring and tiltable upon adjustment of said portions about a point located substantially on the axis of the electrode and in a plane normal to the axis and passing through the device, and adjustment means connected to the ring for adjusting the portions of the ring with respect to the seat and for retaining the portions and electrode in adjusted positions.

5. In an electron tube having an envelope, the combination of a hollow electrode, a second electrode positioned within the hollow electrode, and supporting means adjustably supporting the second electrode within the hollow electrode comprising a support embodying a seat fixedly mounted within the envelope and a ring in spaced overlying relation to the seat and connected thereto, the ring having portions individually adjustable toward and away from the seat, the second electrode being mounted on the ring and tiltable upon adjustment of said portions about a point located substantially on the axis of the second electrode and in a plane normal to the axis and passing through the support, and adjustment means connected to the ring for adjusting the portions of the ring with respect to the seat and for retaining the second electrode in adjusted position within the hollow electrode.

6. In an electron tube having an envelope, the combination of a hollow electrode, a second electrode positioned within the hollow electrode, and means adjustably supporting the second electrode within the hollow electrode comprising an annular mount fixedly mounted within the envelope, an annular support member on the mount and embodying a substantially planar annular seat sescured to the mount and a substantially planar ring in spaced overlying relation to the seat and resiliently con nected thereto, the ring having portions individually adjustable toward and away from the seat, the second electrode being mounted on the ring and tiltable uponadjustment of said portions about a point located substantially on the axis of the second electrode and in a plane normal to the axis and passing through the support, and adjustment means connected to the ring for adjusting the portions of the ring with respect to the seat and for retaining the second electrode in adjusted position within the hollow electrode.

7. The combination in an electron tube of an envelope,

a hollow electrode connected with and extending along the axis of the envelope, 2. second electrode positioned substantially coaxially within the hollow electrode, and means for adjustably supporting the second electrode within the hollow electrode comprising a number of conductors extending through the envelope, an annular mount on the inner ends of the conductors and lying in a plane substantially normal to the axis of the hollow electrode, an annular support member on the mount and embodying a substantially planar annular seat secured to the mount and a substantially planar ring in spaced overlying relation to the seat and resiliently connected thereto, the ring having portions individually adjustable toward and away from the seat, the second electrode being mounted on the ring and tiltable upon adjustment of said portions about a point located substantially on the axis References Cited in the file of this patent UNITED STATES PATENTS 2,277,148 Ronci Jan. 30, 1941 2,310,822 Wheeler Feb. 9, 1943 2,445,814 Wing et a1. Apr. 4, 1946 2,462,877 Litton Mar. 1, 1949 2,520,016 Ronci et al. Apr. 22, 1950 

